This invention relates generally to machines for severing standing crops from the ground using a plurality of rotatable discs having knives mounted thereon to sever standing crop by an impact action upon rotation of the discs and, more particularly, to disc cutter knives that may be easily removed from the rotatable discs and replaced without the need for tools.
Rotary disc mowers are well known in the agricultural arts and used in the harvest of a variety of standing crops. A typical disc mower cutterbar comprises a plurality of cutterheads spaced along the length of the cutterbar. The cutterheads each typically comprise a rotating cutting disc including diametrically opposed cutting blades (though configurations with three or more blades are known) driven by a drivetrain housed within the cutterbar that receives motive power from the prime mover to which the disc mower is attached. For background information on the structure and operation of some typical disc cutterbars, reference is made to U.S. Pat. No. 5,996,323, issued to Campbell, the descriptive portions thereof being incorporated herein in full by reference.
Cutterbars frequently impact rocks and other obstructions in a field which can damage the knives. Further, knives also become dulled by their interaction with the crop and require periodic removal for sharpening or replacement. Knives were originally secured to the rotating discs using a bolt-and-nut connection. Increasing demands for production efficiency yielded numerous connection designs that enable knives to be removed and replaced more quickly, most retaining the bolt and nut, but no longer necessitating complete removal of the bolt and nut. Still, the known disc cutter knife quick change designs require tools to remove and replace the knives.
It would be advantageous to have a knife for use on a rotary disc cutterhead that could be quickly and conveniently removed and replaced by hand without the need for tools. The quick change connection must reliably retain the knives in position during cutterbar operation to prevent knifes from becoming hazardous projectiles, even as the knives impact standing crop or immovable obstacles in the field.